Don't let the LG V40 hold you back though. If you find something you love or that interests you right now, get it. The G7 is pretty good, and the OnePlus 6 is a great phone for only $529. Plus, LG just announced the LG G7 One. A high-end device that looks like the G7 running stock Android 8.1 Oreo. It's worth consideration too.
These days you can easily find a great phone with plenty to like, big screens, and a similar amazing camera experience. Not to mention most carriers allow upgrades once per year now, instead of two. So, you can probably get the LG V35 or something else that's from 2018 without spending too much money.
And while we're expecting great things from the new LG V40 we just don't have enough information yet to comfortably tell buyers to wait for it. Well, unless you're a huge LG fan and you still have an old LG G5. Wait for the V40 and enjoy a few years worth of solid upgrades.